[llvm] [GlobalOpt] Do not fold away addrspacecasts which may be runtime operations (PR #153753)

[Nikita Popov via llvm-commits]

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@@ -1133,8 +1133,9 @@ static bool
 optimizeOnceStoredGlobal(GlobalVariable *GV, Value *StoredOnceVal,
                          const DataLayout &DL,
                          function_ref<TargetLibraryInfo &(Function &)> GetTLI) {
-  // Ignore no-op GEPs and bitcasts.
-  StoredOnceVal = StoredOnceVal->stripPointerCasts();
+  // Ignore no-op GEPs and bitcasts, but not addrspacecasts that may be runtime
+  // operations.
+  StoredOnceVal = StoredOnceVal->stripPointerCastsSameRepresentation();
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nikic wrote:

Yes, but both bitcasts and 0-index GEPs get optimized away.

https://github.com/llvm/llvm-project/pull/153753